Safety of the APOLLO Onyx delivery microcatheter for embolization of brain arteriovenous malformations: results from a prospective post-market study.

BACKGROUND: Catheter retention and difficulty in retrieval have been observed during embolization of brain arteriovenous malformations (bAVMs) with the Onyx liquid embolic system (Onyx). The Apollo Onyx delivery microcatheter (Apollo) is a single lumen catheter designed for controlled delivery of Onyx into the neurovasculature, with a detachable distal tip to aid catheter retrieval. This study evaluates the safety of the Apollo for delivery of Onyx during embolization of bAVMs. METHODS: This was a prospective, non-randomized, single-arm, multicenter, post-market study of patients with a bAVM who underwent Onyx embolization with the Apollo between May 2015 and February 2018. The primary endpoint was any catheter-related adverse event (AE) at 30 days, such as unintentional tip detachment or malfunction with clinical sequelae, or retained catheter. Procedure-related AEs (untoward medical occurrence, disease, injury, or clinical signs) and serious AEs (life threatening illness or injury, permanent physiological impairment, hospitalization, or requiring intervention) were also recorded. RESULTS: A total of 112 patients were enrolled (mean age 44.1±17.6 years, 56.3% men), and 201 Apollo devices were used in 142 embolization procedures. The mean Spetzler-Martin grade was 2.38. The primary endpoint was not observed (0/112, 0%). The catheter tip detached during 83 (58.5%) procedures, of which 2 (2.4%) were unintentional and did not result in clinical sequelae. At 30 days, procedure related AEs occurred in 26 (23.2%) patients, and procedure-related serious AEs in 12 (10.7%). At 12 months, there were 3 (2.7%) mortalities, including 2 (1.8%) neurological deaths, none of which were device-related. CONCLUSION: This study demonstrates the safety of Apollo for Onyx embolization of bAVMs. CLINICAL TRIAL REGISTRATION: CNCT02378883.

Lateral inferior cerebellar peduncle approach to dorsolateral medullary cavernous malformation.

OBJECT: Brainstem cavernous malformations (BSCMs) present a unique therapeutic challenge to neurosurgeons. Resection of BSCMs is typically reserved for lesions that reach pial or ependymal surfaces. The current study investigates the lateral inferior cerebellar peduncle as a corridor to dorsolateral medullary BSCMs. METHODS: In this retrospective review, the authors present the cases of 4 patients (3 women and 1 man) who had a symptomatic dorsolateral cavernous malformation with radiographic and clinical evidence of hemorrhage. RESULTS: All patients underwent excision of the cavernous malformation via a far-lateral suboccipital craniotomy through the foramen of Luschka and with an incision in the inferior cerebellar peduncle. On intraoperative examination, 2 of the 4 patients had hemosiderin staining on the surface of the peduncle. All lesions were completely excised and all patients had a good or excellent outcome (modified Rankin Scale scores of 0 or 1). CONCLUSIONS: This case series illustrates that intrinsic lesions of the dorsolateral medulla can be safely removed laterally through the foramen of Luschka and the inferior cerebellar peduncle.

Histopathological assessment of fatal ipsilateral intraparenchymal hemorrhages after the treatment of supraclinoid aneurysms with the Pipeline Embolization Device.

OBJECT: Delayed ipsilateral intraparenchymal hemorrhage has been observed following aneurysm treatment with the Pipeline Embolization Device (PED). The relationship of this phenomenon to the device and/or procedure remains unclear. The authors present the results of histopathological analyses of the brain sections from 3 patients in whom fatal ipsilateral intracerebral hemorrhages developed several days after uneventful PED treatment of supraclinoid aneurysms. METHODS: Microscopic analyses revealed foreign material occluding small vessels within the hemorrhagic area in all patients. Further analyses of the embolic materials using Fourier transform infrared (FTIR) spectroscopy was conducted on specimens from 2 of the 3 patients. Although microscopically identical, the quantity of material recovered from the third patient was insufficient for FTIR spectroscopy. RESULTS: FTIR spectroscopy showed that the foreign material was polyvinylpyrrolidone (PVP), a substance that is commonly used in the coatings of interventional devices. CONCLUSIONS: These findings are suggestive of a potential association between intraprocedural foreign body emboli and post-PED treatment-delayed ipsilateral intraparenchymal hemorrhage.

Microsurgical treatment of pediatric intracranial aneurysms: long-term angiographic and clinical outcomes.

BACKGROUND: Pediatric aneurysms are rare and complex to treat. Long-term angiographic and clinical data after microsurgical or endovascular therapies are lacking. OBJECTIVE: To study the clinical and radiographic outcomes in aneurysms in pediatric patients treated with microsurgery. METHODS: Between 1989 and 2005, 48 patients

Pleomorphic xanthoastrocytoma presenting with life-threatening hemorrhage in a child.

Pleomorphic xanthoastrocytomas are glial-based tumors that arise most frequently in young patients and usually follow a more benign and indolent clinical course than their other glial-based tumor counterparts. These tumors most frequently present with seizures, and only 3 previous case reports exist of hemorrhagic tumor as the clinical presentation. The authors present the first case of life-threatening intracerebral hemorrhage from pleomorphic xanthoastrocytoma in a child.

Resolution of mydriatic pupil after angioplasty and stenting of cervical internal carotid artery dissection: case report.

OBJECTIVE: A patient with cervical internal carotid artery (ICA) dissection presented with visual loss and a mydriatic pupil that resolved after angioplasty and stenting. CLINICAL PRESENTATION: A 49-year-old woman presented with a unilateral dilated tonic pupil and transient monocular visual loss and subsequently developed speech disturbance. Angiography revealed a left cervical ICA dissection with significant luminal narrowing. The ophthalmic artery filled retrograde through external carotid artery branches and reconstituted the supraclinoid ICA. Computed tomographic perfusion showed significant hypoperfusion of the left hemisphere. Magnetic resonance imaging showed punctate boundary zone infarcts. INTERVENTION: The patient experienced pressure-dependent left hemispheric transient ischemic attacks and pressure-dependent ocular findings despite anticoagulation. She underwent uncomplicated left ICA angioplasty and stenting. The flow through the ophthalmic artery became anterograde. The tonic pupil returned to symmetry with the contralateral pupil, and the patient's symptoms resolved completely. CONCLUSION: Cervical ICA dissection can manifest with a tonic mydriatic pupil. Treatment with angioplasty and stenting of the dissected segment can restore flow and resolve the pupillary abnormality. A pathophysiological mechanism for the mydriasis is proposed.

Surgical treatment of high-risk intracranial dural arteriovenous fistulae: clinical outcomes and avoidance of complications.

OBJECTIVE: An increasing number of intracranial dural arteriovenous fistulae (DAVFs) are amenable to endovascular treatment. However, a subset of patients with high-risk lesions requires surgical intervention for complete obliteration. We reviewed our experience with the surgical management of high-risk intracranial DAVFs and offer recommendations to minimize complications based on fistula location and type. METHODS: Hospital records for 53 patients (16 women, 37 men) with high-risk intracranial DAVFs treated surgically between 1995 and 2004 were reviewed to determine their presenting symptoms, location, endovascular and surgical interventions, angiographic outcome, and treatment complications. Most patients (76%) presented with intracranial hemorrhage, progressive neurological deficits, or seizures. All patients had high-risk angiographic features such as cortical venous drainage or venous varix. Preoperative embolization was performed in 27 patients. Surgical approaches were tailored to the lesion location. Fistulae were located in the transverse-sigmoid junction (n = 18), tentorium (n = 17), ethmoid (n = 7), superior sagittal sinus (n = 6), torcula (n = 4), and sphenoparietal sinus (n = 3). RESULTS: At the time of the last follow-up evaluation, 49 patients (92%) had good or excellent outcomes (Glasgow Outcome Scale score, 4 or 5) and three (6%) were deceased. Five patients had a residual fistula. One residual spontaneously thrombosed, one was treated with gamma knife radiosurgery, and two were successfully embolized. The overall morbidity and mortality rate was 13%. CONCLUSION: Despite fulminant presenting symptoms, high-risk intracranial DAVFs can be successfully managed with good outcomes. When anatomic features prevent endovascular access, or embolization fails to obliterate the lesion, urgent surgical treatment is indicated. Patients with residual filling of the DAVF should be considered for adjuvant therapy, including further embolization or radiosurgery.

Giant, partially thrombosed aneurysm develops after remote angiographically negative subarachnoid hemorrhage: case report.

OBJECTIVE: This is the first report of the rupture of a giant aneurysm in a patient who sustained a remote angiographically negative subarachnoid hemorrhage (SAH). CLINICAL PRESENTATION: A 62-year old woman initially presented with a Fisher Grade III SAH 9 years ago. Her evaluation, which included cerebral angiography, magnetic resonance imaging scans, and magnetic resonance angiography of the head and neck, failed to reveal the cause of the hemorrhage. Nine years after her initial hemorrhage, the patient presented with a Fisher Grade IV SAH and a giant right supraclinoid internal carotid artery aneurysm. INTERVENTION: Computed tomographic and catheter angiography showed a partially thrombosed giant aneurysm of the right supraclinoid internal carotid artery. She underwent clip reconstruction and obliteration of the aneurysm. Review of her previous angiograms and magnetic resonance imaging scans did not show an aneurysm in its nascency. CONCLUSION: Initial catheter angiography and magnetic resonance imaging scans may fail to disclose a subtle dissection or blister aneurysm as a cause for SAH. As in our case, the dissection or blister may progress to a giant aneurysm with time.

Application of a novel headrest system for odontoid screw fixation. Technical note.

The authors describe a unique headholder device adapted to facilitate the placement of anterior odontoid screws. The patient's head is affixed in the headholder equipped with an articulating arm that can be placed in a paramedian fashion. This configuration rigidly fixates the head and provides an unencumbered open-mouth view of the odontoid using radiographic images, thus making screw placement easier.

Durectomy and reconstruction for the treatment of a recurrent spinal meningioma. Case report.

The management of spinal meningiomas with extensive involvement of the dura mater is controversial. The principal difficulty in performing a resection is the potential for complications associated with this approach. The authors present the case of a pregnant 35-year-old woman in whom bilateral lower-extremity numbness, weakness, gait ataxia, and myelopathy developed. Magnetic resonance imaging showed a recurrent thoracic meningioma with extensive infiltration of the dura mater. Durectomy, complete resection, and reconstruction were performed. The patient has not experienced a recurrence 21 months after her treatment. This case illustrates that thoracic spinal meningiomas with extensive dural involvement can be resected safely with a complete durectomy. The novel dural reconstruction involving the implantation of a fascia lata and bovine pericardium allograft is an effective way to reconstruct the dura to create an adequate barrier to cerebrospinal fluid.

Endovascular reconstruction with the Neuroform stent as monotherapy for the treatment of uncoilable intradural pseudoaneurysms.

OBJECTIVE: Intradural pseudoaneurysms have a malignant natural history and can be difficult to treat if parent vessel deconstruction is not feasible. These lesions often involve a long arterial segment and lack a defined saccular component that would safely accommodate the introduction of embolization coils. The current report describes the successful endovascular treatment of these lesions using a strategy of Neuroform stent reconstruction. METHODS: A retrospective review of the prospectively maintained Neuroform databases from our two institutions identified all intracranial aneurysms treated with the Neuroform stent alone, without embolization coils. The clinical charts, procedural data, and angiographic results were reviewed. RESULTS: Over a 38-month study period (10/02-2/06), 266 aneurysms were treated with the Neuroform stent. Of these, 10 were small "uncoilable" intradural pseudoaneurysms associated with subarachnoid hemorrhage. These lesions were treated using a strategy of endovascular stent reconstruction of the diseased vascular segment with one or more Neuroform stents (without concomitant coil embolization). Seven pseudoaneurysms were treated in the context of acute or subacute subarachnoid hemorrhage, and three were associated with a remote history of subarachnoid hemorrhage. Periprocedural complications occurred in two patients (clinically silent, intraprocedural thromboembolic event successfully treated with intra-arterial abciximab, symptomatic postprocedural stent thrombosis with successful thrombolysis, and excellent neurological recovery). Both complications occurred in patients with ruptured aneurysms and could be attributed to inadequate platelet inhibition at the time of the initial procedure. Follow-up conventional angiographic examinations were available for all 10 patients with pseudoaneurysms (1-18.5 mo; average, 9.0 mo). In nine cases, the aneurysms improved at follow-up, with either complete (n = 5) or near complete (n = 4) resolution. In one case, short-term follow-up (1 mo) demonstrated no significant change. No patient has rehemorrhaged after treatment. CONCLUSION: Endovascular Neuroform stent reconstruction represents an optimal strategy for the management of intradural pseudoaneurysms that require a constructive treatment strategy and are too small to accommodate the introduction of embolization coils. Nine out of 10 patients in the current series treated with this strategy demonstrated some degree of endovascular remodeling with either complete (n = 5) or partial (n = 4) angiographic resolution at follow-up. No rehemorrhages were encountered. Adequate antiplatelet therapy, even in the setting of acute subarachnoid hemorrhage, is prerequisite for the avoidance of thromboembolic complications.

Quantification and comparison of telovelar and transvermian approaches to the fourth ventricle.

OBJECTIVE: To quantify the exposure to the fourth ventricle obtained with the telovelar and transvermian approaches. METHODS: The telovelar, with and without C1 posterior arch removal, and transvermian approaches were performed on six cadaveric heads. The area of surgical exposure was calculated from triangles formed by defined anatomic points. A robotic microscope was used to determine the "angle of approach" for the same points. RESULTS: The maximal allowable vertical angle of attack to the obex of the fourth ventricle was significantly greater with the telovelar approach than with the transvermian approach (P < 0.002), but there was no difference at the rostral fourth ventricle. The maximal allowable horizontal angle of attack at the level of the obex, Luschka, and rostral fourth ventricle was significantly greater with the telovelar than with the transvermian approach (P < 0.001). Removal of the C1 posterior arch with the telovelar approach significantly increased the vertical angle of approach to the obex (P < 0.001) and rostral aspect of the fourth ventricle (P = 0.005) compared with the telovelar alone. The telovelar approach with C1 arch removal offered a larger working area than the transvermian approach (P < 0.001). CONCLUSION: Except for the vertical angle to the rostral aspect of the fourth ventricle, the telovelar approach provides greater angle of exposure in all planes than the transvermian approach. Removal of the C1 posterior arch obviates this sole advantage of the transvermian approach. The telovelar approach offers a corridor through noneloquent arachnoid planes and a safe and capacious working environment.

Surgical management of distal coil migration and arterial perforation after attempted coil embolization of a ruptured ophthalmic artery aneurysm: technical case report.

OBJECTIVE AND IMPORTANCE: Distal coil migration is a rare but hazardous complication of aneurysm coil embolization. Various microsnare devices have been developed to address this problem. We describe the surgical management of a case in which microsnare retrieval failed. CLINICAL PRESENTATION: A 34-year-old woman presented with subarachnoid hemorrhage. Magnetic resonance imaging, computed tomography angiography, and conventional angiography showed an approximately 2.5-mm ophthalmic artery aneurysm. Using balloon remodeling, a 2 x 4-cm coil was deployed into the aneurysm fundus. While the coil pusher was being removed after deployment, the microcatheter advanced abruptly into the aneurysm. The coil mass was dislodged and migrated into the angular branch of the middle cerebral artery. Contrast extravasation was noted during attempted retrieval with a microsnare device. TECHNIQUE: Computed tomographic scans showed a subarachnoid hemorrhage in the territory of the left frontotemporal operculum. A left modified orbitozygomatic approach was performed. The coil mass was removed from the angular artery and a thromboembolectomy was performed. The artery was repaired and the pseudoaneurysm was clip ligated. The ophthalmic artery aneurysm was clip ligated. The patient recovered without deficits. CONCLUSION: Distal coil migration and arterial perforation can be treated surgically with a good clinical outcome.

Long-term clinical and angiographic follow-up of unclippable wrapped intracranial aneurysms.

OBJECTIVE: This is the largest contemporary series examining long-term clinical and angiographic follow-up of unclippable wrapped intracranial aneurysms. METHODS: The presentation, location and shape of aneurysm, wrapping technique, outcome at discharge and last follow-up, and change in aneurysm at last angiographic follow-up were reviewed retrospectively in 74 patients with wrapped or clip-wrapped aneurysms. Patients in whom wrapping was used in conjunction with primary clipping were excluded. RESULTS: Of the 74 patients, 11 were lost to follow-up. The mean age of the remaining 63 patients (16 males, 47 females) was 56.5 years (range, 13-89 yr). Fifty-one aneurysms were located in the anterior circulation, and 17 were located in the posterior circulation. Fourteen patients presented with a ruptured aneurysm. Seventeen aneurysms were fusiform. Seven aneurysms were clip-wrapped, and 61 were wrapped with cotton. At discharge the Glasgow Outcome Scale (GOS) score was 5 in 54 patients and 4 in 5 patients. Two patients died from their presenting hemorrhage, and one from a medical comorbidity. The mean clinical follow-up was 44.1 months (range, 1-120 mo). One patient under clinical follow-up experienced subarachnoid hemorrhage. The mean angiographic follow-up of 34 patients was 41.8 months (range, 3-120 mo). During this follow-up period, no patient's aneurysm changed in size or configuration. CONCLUSION: Wrapping or clip-wrapping of unclippable intracranial aneurysms is safe and seems to confer protection against aneurysmal growth or subarachnoid hemorrhage.

Resolution of hemifacial spasm after surgical obliteration of a tentorial arteriovenous fistula: case report.

OBJECTIVE AND IMPORTANCE: We describe a patient with a tentorial dural arteriovenous fistula who presented with ipsilateral hemifacial spasm. CLINICAL PRESENTATION: A 50-year-old man sought treatment for left facial twitching that worsened over 6 months. Magnetic resonance imaging and catheter angiography demonstrated a left tentorial dural arteriovenous fistula. INTERVENTION: The patient underwent a retrosigmoid craniotomy and ligation of the draining vein at the site of the fistula. Intraoperative angiography showed complete obliteration of the fistula. The patient's hemifacial spasm improved significantly after the fistula was obliterated. CONCLUSION: Posterior fossa arteriovenous fistulas can present with a hemifacial spasm related to compression of the facial nerve by arterialized leptomeningeal veins. Microsurgical obliteration of the fistula can resolve the related symptoms.

Combined skull base approaches to the posterior fossa. Technical note.

Combined approaches to the skull base provide maximal exposure of the complex and eloquent anatomical structures contained within the posterior fossa. Common to these combined exposures are variable degrees of petrous bone removal. Understanding the advantages of each approach is critical when attempting to balance increases in operative exposure against the risk of potential complications. Despite their risks, aggressive combined exposures to the posterior fossa enable the greatest degree of visualization of the anatomy. Consequently, surgeons can approach lesions with maximal margins of safety, which cannot otherwise be realized. To minimize morbidity in all cases, the approach chosen must be applied individually, depending on the lesion and the patient's characteristics.

Monorail snare technique for the recovery of stretched platinum coils: technical case report.

OBJECTIVE AND IMPORTANCE: Coil stretching represents a potentially hazardous technical complication not infrequently encountered during the embolization of cerebral aneurysms. Often, the stretched coil cannot be advanced into the aneurysm or withdrawn intact. The operator is then forced to attempt to retract the damaged coil, which may result in coil breakage, leaving behind a significant length of potentially thrombogenic stretched coil material within the parent vessel. To overcome this problem, we devised a technique to snare the distal, unstretched, intact portion of the platinum coil by use of the indwelling microcatheter and stretched portion of the coil as a monorail guide. CLINICAL PRESENTATION: We have used this technique successfully in four patients to snare coils stretched during cerebral aneurysm embolization. Three of these patients were undergoing Neuroform (Boston Scientific/Target, Fremont, CA) stent-supported coil embolization of unruptured aneurysms. In all cases, the snare was advanced easily to the targeted site for coil engagement by use of the microcatheter as a monorail guide. Once the intact distal segment of the coil was ensnared, coil removal was uneventful, with no disturbance of the remainder of the indwelling coil pack or Neuroform stent. TECHNIQUE: A 2-mm Amplatz Goose Neck microsnare (Microvena Corp., White Bear Lake, MN) was placed through a Prowler-14 microcatheter (Cordis Corp., Miami, FL). The hub of the indwelling SL-10 microcatheter (Boston Scientific, Natick, MA) was then cut away with a scalpel, leaving the coil pusher wire intact, and removed. The open 2-mm snare was then advanced over the outside of the coil pusher wire and microcatheter. The snare and Prowler-14 microcatheter were then advanced into the guiding catheter (6- or 7-French) as a unit over the indwelling SL-10 microcatheter. By use of the SL-10 microcatheter and coil as a "monorail" guide, the snare was advanced over and beyond the microcatheter and the stretched portion of the coil until the snare was in position to engage the distal unstretched coil. At this point, the snare was then closed around the intact portion of the coil, and the microcatheters, snare, and coil were removed as a unit. CONCLUSION: The monorail snare technique represents a fast, safe, and easy method by which a stretched coil can be removed.

Antiplatelet therapy in neuroendovascular therapeutics.

Our understanding of the pharmacology of antiplatelet therapy continues to evolve rapidly. Although the existing data are primarily generated in the setting of interventional and preventative cardiology studies, these data may be extrapolated to guide the rational application of these agents in neuroendovascular procedures. Platelet function testing represents an increasingly available and practical method by which to verify the adequacy of therapy and guide clinical decision making. The optimal application of these agents will undoubtedly improve the risk profile of neuroendovascular procedures, increase the success rate of acute stroke intervention, and facilitate more effective secondary stroke prevention.

Usefulness of the Neuroform stent for the treatment of cerebral aneurysms: results at initial (3-6-mo) follow-up.

OBJECTIVE: The Neuroform microstent, a flexible, self-expanding, nitinol stent specifically designed for use in the cerebral vasculature, became available in North America for aneurysm treatment in November 2002. The present report details our experience with the Neuroform stent over the past 2 years, with an emphasis on evolving treatment strategies and treatment durability at initial (3-6 mo) follow-up. METHODS: All patients included in this report were registered in a prospectively maintained database. We assessed the clinical history, indications for stent use, aneurysm dimensions, technical details of the procedures, degree of aneurysm occlusion, angiographic and clinical findings at follow-up, and complications. RESULTS: Over a 20-month period, 64 patients with 74 aneurysms were treated with 86 Neuroform stents. Of 64 patients, 16 (25%) were treated in the context of subarachnoid hemorrhage (8 acute, 7 subacute, 1 remote). Indications for stent use included broad aneurysm neck (n = 51 stents; average neck, 5.1 mm; aneurysm size, 8.2 mm), fusiform/dissecting morphology (n = 17), salvage/bailout for coils prolapsed into the parent vessel (n = 7), and giant aneurysm (n = 11). Sixty-one aneurysms were stented and coiled with complete or near complete (>95%) occlusion in 28 patients (45.9%) and partial occlusion (<95%) in 33 patients (54%). Follow-up angiographic (n = 43) or magnetic resonance angiographic (n = 5) data (average follow-up, 4.6 mo; median, 4 mo; range, 1.5-13 mo) for 48 aneurysms (46 patients) after stent-supported coil embolization demonstrated progressive thrombosis in 25 patients (52%), recanalization in 11 patients (23%) (8 of whom were retreated), and no change in 12 patients (25%). Follow-up angiography in 5 additional patients with dissecting aneurysms treated with stents alone demonstrated interval vascular remodeling with decreased aneurysm size in all patients. Delayed, severe, in-stent stenosis was observed in 3 patients, 1 of whom was symptomatic and required angioplasty and subsequently superficial temporal artery-to-middle cerebral artery bypass surgery. Using the second-generation Neuroform2 delivery system (n = 53), very few technical problems with stent delivery and deployment have been encountered (n = 2). CONCLUSION: The Neuroform stent facilitates adequate embolization of complex cerebral aneurysms, which would not otherwise be amenable to endovascular therapy. Initial follow-up data indicate favorable progressive thrombosis and recanalization rates for aneurysms after Neuroform stent-assisted embolization. These advantages of stenting were most evident for small aneurysms with wide necks.

Use of "bonnet" bypass with radial artery interposition graft in a patient with recurrent cranial base carcinoma: technical report of two cases and review of the literature.

OBJECTIVE AND IMPORTANCE: Two patients with recurrent cranial base carcinomas involving the carotid artery received a "bonnet" bypass using the contralateral superficial temporal artery as the donor vessel because the ipsilateral common and external carotid arteries were unavailable. The radial artery was used as the graft. CLINICAL PRESENTATION: A 58-year-old man with ear pain and an enlarging mass involving the left cranial base and neck had undergone a right partial glossectomy and modified neck dissection followed by radiotherapy for squamous cell carcinoma. Recurrent carcinoma extensively involved the left internal carotid artery. A 46-year-old man with jaw pain and hoarseness had undergone multiple resections and radiation therapy for medullary thyroid carcinoma. Magnetic resonance imaging showed recurrent tumor on the right. INTERVENTION: Both patients underwent a pterional craniotomy. The supraclinoid internal carotid artery was exposed. The radial artery was harvested. The contralateral superficial temporal artery was dissected at its bifurcation into the frontal and parietal branches. The radial artery graft was anastomosed to the superficial temporal artery and a recipient ipsilateral branch of the middle cerebral artery. The internal carotid artery was clip-ligated. After surgery, both patients remained neurologically stable. Angiography confirmed that the bypasses were patent and that the middle cerebral artery territory filled. The patients' carcinomas were resected aggressively. CONCLUSION: When aggressive resection of cranial base tumors is needed and the ipsilateral carotid artery is unavailable as a donor vessel, a "bonnet" bypass with carotid artery sacrifice may be performed. Compared with vein grafts, microsurgical anastomosis is easier and the patency rate is higher with a radial artery graft.